Editing Diprotodon (section)

==Palaeoecology==
''Diprotodon'' was present across the entire Australian continent by the Late Pleistocene,<ref name=Price2021/> especially following MIS5 approximately 110,000 years ago.<ref name=Price2009/> The onset of the [[Quaternary glaciation]], with the continuous advance and retreat of glaciers at the poles, created extreme climatic variability elsewhere. In Australia, the warmer, wetter [[interglacial period]]s were received by forests and woodlands; colder, dryer [[glacial period]]s were more conducive to grasslands and deserts. The continent progressively became dryer as the Asian [[monsoon]]s became less influential over Australia: the vast interior had become arid and sandy by 500,000 years ago; the mega-lakes that were once prominent, especially during interglacials in north-western Australia, dried up; and the rainforests of eastern Australia gradually retreated. Aridity has hastened over the last 100,000 years, especially after 60,000 years ago with surging [[El Niño–Southern Oscillation]]s.<ref name=Black2012/>

The continent-wide distribution of ''Diprotodon'' indicates herds trekked across almost any habitat,<ref>{{Cite journal |last=Webb |first=Steve |date=20 January 2009 |title=Late Quaternary distribution and biogeography of the southern Lake Eyre basin (SLEB) megafauna, South Australia |url=https://onlinelibrary.wiley.com/doi/10.1111/j.1502-3885.2008.00044.x |journal=[[Boreas (journal)|Boreas]] |language=en |volume=38 |issue=1 |pages=25–38 |doi=10.1111/j.1502-3885.2008.00044.x |bibcode=2009Borea..38...25W |issn=0300-9483 |access-date=6 May 2024 |via=Wiley Online Library}}</ref> much like modern African elephants south of the [[Sahara]].<ref name=Price2008/> ''Diprotodon'' was a member of a diverse assemblage of megafauna that were [[endemism|endemic]] to Pleistocene Australia; these also included the [[thylacine]], modern kangaroos, [[Sthenurinae|sthenurines]] (giant short-faced kangaroos), a diversity of modern and giant koala and wombat species,<ref name=Black2012/> the [[tapir]]-like ''[[Palorchestes]]'', the giant turtle ''[[Meiolania]]'', and the giant bird ''[[Genyornis]]''.<ref name=Flannery1990/> ''Diprotodon'' coexisted with the diprotodontid ''[[Zygomaturus|Zygomaturus trilobus]]'', which appears to have remained in the forests, whereas ''Diprotodon'' foraged the expanding grasslands and woodlands. Other contemporaneous dipotodontids (''[[Hulitherium]]'', ''Z. nimborensia'', and ''[[Maokopia]]'') were insular forms that were restricted to the forests of New Guinea.<ref name=Black2012/>

===Predation===
Due to its massive size, ''Diprotodon'' would have been a tough adversary for native carnivores. It contended with the largest-known marsupial predator ''[[Thylacoleo carnifex]]''; while ''Diprotodon'' remains that were gnawed or bitten by ''T. carnifex'' have been identified, it is unclear if the {{cvt|100|–|130|kg}} marsupial predator was powerful enough to kill an animal surpassing {{cvt|2000|kg}}. The modern [[jaguar]], at half the size of ''T. carnifex'', can kill a {{cvt|500|kg}} bull so it is possible ''T. carnifex'' could have killed small ''Diprotodon''.<ref>{{cite journal|last1=Wroe|first1=S.|last2=Myers|first2=T. J.|last3=Wells|first3=R. T.|last4=Gillespie|first4=A.|year=1999|title=Estimating the weight of the Pleistocene marsupial lion, ''Thylacoleo carnifex'' (Thylacoleonidae:Marsupialia): implications for the ecomorphology of a marsupial super-predator and hypotheses of impoverishment of Australian marsupial carnivore faunas|journal=Australian Journal of Zoology |volume=47|issue=5|page=495|doi=10.1071/zo99006}}</ref> Similar to recent kangaroos with thylacines or [[quoll]]s, juvenile ''Diprotodon'' may have been at high risk of predation by ''T. carnifex''; it and fossils of juvenile ''Diprotodon'' have been recovered from the same caves.{{sfn|Owen|1870|loc=p. 568}}

The largest predators of Australia were reptiles, most notably the [[saltwater crocodile]], the now-extinct crocodiles ''[[Paludirex]]'' and ''[[Quinkana]]'', and the giant lizard [[megalania]] (''Varanus priscus''). At {{cvt|7|m}} in length, megalania was the largest carnivore of Pleistocene Australia.<ref name=Flannery1990>{{cite journal|last=Flannery|first=T. F.|year=1990|title=Pleistocene faunal loss: implications of the aftershock for Australia's past and future|journal=Archaeology in Oceania|volume=25|issue=2|pages=45–55|doi=10.1002/j.1834-4453.1990.tb00232.x}}</ref>

===Extinction===

As part of the [[Quaternary extinction event]], ''Diprotodon'' and every other Australian land animal heavier than {{cvt|100|kg}} became extinct. The timing and the exact cause are unclear because there is poor resolution on the ages of Australian fossil sites. Since their discovery, the extinction of the Australian megafauna has usually been blamed on the changing climate or overhunting by the first [[Aboriginal Australian]]s.<ref name=David2021/> In 2001, Australian palaeontologist Richard Roberts and colleagues dated 28 major fossil sites across the continent, and were able to provide a precise date for megafaunal extinction. They found most disappear from the fossil record by 80,000 years ago, but ''Diprotodon''; the giant wombat ''[[Phascolonus]]''; ''Thylacoleo''; and the short-faced kangaroos ''[[Procoptodon]]'', ''[[Protemnodon]]'', and ''[[Simosthenurus]]'' were identified at [[Ned's Gully]], Queensland, and [[Kudjal Yolgah Cave]], Western Australia, which they dated to respectively 47,000 and 46,000 years ago. Thus, all of the Australian Pleistocene megafauna died out probably between about 50,000 and 41,000 years ago. There also seems to have been a diverse assemblage of megafauna just before their extinction, and all populations across at least western and eastern Australia died out at about the same time.<ref name="New Ages">{{cite journal|last1=Roberts |first1=R.G.|last2=Flannery |first2=T.F. |author2-link=Tim Flannery|author3=Ayliffe, L.K. |author4=Yoshida, H. |author5=Olley, J.M.|author6=Prideaux, G.J. |author7=Laslett, G.M. |author8=Baynes, A.|author9=Smith, M.A. |author10=Jones, R. |author11=Smith, B.L.|year=2001|title = New ages for the last Australian megafauna: Continent-wide extinction about 46,000&nbsp;years ago|journal=[[Science (journal)|Science]]|volume = 292 |issue = 5523 |pages = 1888–1892|doi=10.1126/science.1060264 |pmid=11397939|bibcode=2001Sci...292.1888R |s2cid=45643228|url = http://www.uow.edu.au/content/groups/public/@web/@sci/@eesc/documents/doc/uow014698.pdf}}</ref> As of 2021, there is still no solid evidence of megafauna surviving past approximately 40,000 years ago; their latest occurrence, including ''Diprotodon'', is recorded at South Walker Creek mine in the north-east at about 40,100 ± 1,700 years ago.<ref name=David2021>{{cite journal|first1=B.|last1=David|first2=L. J.|last2=Arnold|first3=J.-J.|last3=Delannoy|first4=J.|last4=Fresløve|first5=C.|last5=Urwin|first6=F.|last6=Petchey|first7=M. C.|last7=McDowell|first8=R.|last8=Mullette|first9=G.|last9=Kurnai|first10=J.|last10=Mialanes|first11=R.|last11=Wood|first12=J.|last12=Crouch|first13=J.|last13=Berthet|first14=V. N. L.|last14=Wong|first15=H.|last15=Green|first16=J.|last16=Hellstrom|year=2021|title=Late survival of megafauna refuted for Cloggs Cave, SE Australia: Implications for the Australian Late Pleistocene megafauna extinction debate|journal=Quaternary Science Reviews|volume=253|page=106781|doi=10.1016/j.quascirev.2020.106781|bibcode=2021QSRv..25306781D |s2cid=234010059 }}</ref>

At the time Roberts ''et al.'' published their paper, the earliest evidence of human activity in Australia was 56±4 thousand years old, which is close to their calculated date for the megafauna extinction; they hypothesised human hunting had eradicated the last megafauna within about 10,000 years of coexistence. Human hunting had earlier been blamed for the extinction of North American and [[List of extinct New Zealand animals|New Zealand]] megafauna.<ref name="New Ages"/> Human activity was then generally regarded as the main driver of Australian megafaunal extinction, especially because the megafauna had survived multiple extreme drought periods during glacial periods. At the time, there did not seem to be any evidence of unusually extreme climate during this period.<ref name=Murphy2011>{{cite journal|first1=B. P.|last1=Murphy|first2=G. J.|last2=Williamson|first3=D. M. J. S.|last3=Bowman|year=2011|title=Did central Australian megafaunal extinction coincide with abrupt ecosystem collapse or gradual climate change?|journal=Global Ecology and Biogeography|volume=21|issue=2|pages=142–151|doi=10.1111/j.1466-8238.2011.00668.x}}</ref> Due to the slowness of marsupial reproduction, even limited megafaunal hunting may have severely weakened the population.<ref name=Tyndale2001/><ref name=Brook2006>{{cite journal|last1=Brook|first1=B. W.|last2=Johnson|first2=C. N.|year=2006|title=Selective hunting of juveniles as a cause of the imperceptible overkill of the Australian Pleistocene megafauna|journal=Alcheringa: An Australasian Journal of Palaeontology |volume=30|pages=39–48|doi=10.1080/03115510609506854|bibcode=2006Alch...30S..39B |s2cid=84205755 }}</ref>

[[File:Fire-stick- Lycett.webp|thumb|upright=1.3|The [[Aboriginal Australian]] practice of [[fire-stick farming]] (above depicts a [[kangaroo]] hunt) may be implicated in megafaunal extinction.<ref name=Miller2005/><ref name=David2021/>]]

In 2005, American geologist Gifford Miller noticed fire abruptly becomes more common about 45,000 years ago; he ascribed this increase to aboriginal [[fire-stick farming|fire-stick farmers]], who would have regularly started [[controlled burn]]s to clear highly productive forests and grasslands. Miller said this radically altered the vegetational landscape and promulgated the expanse of the modern-day fire-resilient scrub at the expense of the megafauna.<ref name=Miller2005>{{cite journal|first1=G. H.|last1=Miller|first2=M. L.|last2=Fogel|first3=J. W.|last3=Magee|first4=M. K.|last4=Gagan|first5=S. J.|last5=Clarke|first6=B. J.|last6=Johnson|year=2005|title=Ecosystem Collapse in Pleistocene Australia and a Human Role in Megafaunal Extinction|journal=Science|volume=309|issue=5732|pages=287–290|doi=10.1126/science.1111288|pmid=16002615 |bibcode=2005Sci...309..287M |s2cid=22761857 |url=http://doc.rero.ch/record/14709/files/PAL_E1537.pdf }}</ref><ref>{{cite journal|last1=Bowman|first1=D.M.J.|last2=Murphy|first2=B.P.|last3=McMahon|first3=C.R.|year=2010|title=Using carbon isotope analysis of the diet of two introduced Australian megaherbivores to understand Pleistocene megafaunal extinctions|journal=Journal of Biogeography|volume=37|issue=3 |pages=499–505|doi=10.1111/j.1365-2699.2009.02206.x |bibcode=2010JBiog..37..499B |s2cid=84274623 }}</ref> Subsequent studies had difficulty firmly linking controlled burns with major ecological collapse.<ref name=Murphy2011/><ref>{{Cite journal|last1=Johnson|first1=Chris N.|last2=Rule|first2=Susan|last3=Haberle|first3=Simon G.|last4=Kershaw|first4=A. Peter|last5=McKenzie|first5=G. Merna|last6=Brook|first6=Barry W.|date=February 2016|title=Geographic variation in the ecological effects of extinction of Australia's Pleistocene megafauna|journal=Ecography|language=en|volume=39|issue=2|pages=109–116|doi=10.1111/ecog.01612|doi-access=free|bibcode=2016Ecogr..39..109J }}</ref><ref>{{Cite journal|last1=Dodson|first1=J.|last2=Field|first2=J.H.|date=May 2018|title=What does the occurrence of ''Sporormiella'' (''Preussia'') spores mean in Australian fossil sequences?|journal=Journal of Quaternary Science|volume=33|issue=4|pages=380–392|doi=10.1002/jqs.3020|bibcode=2018JQS....33..380D|s2cid=133737405 }}</ref> The frequency of fire could have also increased as a consequence of megafaunal extinction because total plant consumption rapidly fell, leading to faster fuel buildup.<ref>{{cite journal|last=Rule|first=S.|author2=Brook, B. W.|author3=Haberle, S. G.|author4=Turney, C. S. M.|author5=Kershaw, A. P.|year=2012|title=The Aftermath of Megafaunal Extinction: Ecosystem Transformation in Pleistocene Australia|journal=Science|volume=335|issue=6075|pages=1483–1486|bibcode=2012Sci...335.1483R|doi=10.1126/science.1214261|pmid=22442481|s2cid=26675232}}</ref>

In 2017, the human-occupied [[Madjedbebe]] rock shelter on the northern Australian coast was dated to about 65,000 years ago, which if correct would mean humans and megafauna had coexisted for over 20,000 years.<ref name="ClarksonJacobs2017">{{cite journal|last1=Clarkson|first1=C.|last2=Jacobs|first2=Z.|last3=Marwick|first3=B.|last4=Fullagar|first4=R.|last5=Wallis|first5=L.|last6=Smith|first6=M.|last7=Roberts|first7=R. G. |title=Human occupation of northern Australia by 65,000 years ago|journal=Nature|volume=547|issue=7663|year=2017|pages=306–310|issn=0028-0836|doi=10.1038/nature22968|pmid=28726833|bibcode=2017Natur.547..306C|hdl=2440/107043|s2cid=205257212|url=https://digital.library.adelaide.edu.au/dspace/bitstream/2440/107043/2/hdl_107043.pdf |archive-url=https://web.archive.org/web/20190428141305/https://digital.library.adelaide.edu.au/dspace/bitstream/2440/107043/2/hdl_107043.pdf |archive-date=2019-04-28 |url-status=live|hdl-access=free}}</ref> Other authors have considered this dating questionable.<ref>{{Cite journal |last1=Williams |first1=Martin A. J. |last2=Spooner |first2=Nigel A. |last3=McDonnell |first3=Kathryn |last4=O'Connell |first4=James F. |date=January 2021 |title=Identifying disturbance in archaeological sites in tropical northern Australia: Implications for previously proposed 65,000-year continental occupation date |url=https://onlinelibrary.wiley.com/doi/10.1002/gea.21822 |journal=Geoarchaeology |language=en |volume=36 |issue=1 |pages=92–108 |doi=10.1002/gea.21822 |bibcode=2021Gearc..36...92W |issn=0883-6353}}</ref> In the 2010s, several ecological studies were published in support of major drought conditions coinciding with the final megafaunal extinctions.<ref name="Wroe2013">{{cite journal |last1=Wroe |first1=S. |last2=Field |first2=J.H. |last3=Archer |first3=M. |last4=Grayson |first4=D.K. |last5=Price |first5=G.J. |last6=Louys |first6=J. |last7=Faith |first7=J.T. |last8=Webb |first8=G.E. |last9=Davidson |first9=I. |last10=Mooney |first10=S.D.|year=2013|title=Climate change frames debate over the extinction of megafauna in Sahul (Pleistocene Australia-New Guinea) |journal=Proceedings of the National Academy of Sciences |volume=110 |issue=22 |pages=8777–8781 |doi=10.1073/pnas.1302698110 |issn=0027-8424 |pmc=3670326 |pmid=23650401 |bibcode=2013PNAS..110.8777W|doi-access=free }}</ref><ref>{{cite journal|first1=T. J.|last1=Cohen|first2=J. D.|last2=Jansen|first3=L. A.|last3=Gliganic|first4=J. R.|last4=Larsen|first5=G. C.|last5=Nanson|first6=J.-H.|last6=May|first7=B. G.|last7=Jones|first8=D. M.|last8=Price|title=Hydrological transformation coincided with megafaunal extinction in central Australia|journal=Geology|volume=43|year=2015|issue=3 |pages=195–198|doi=10.1130/G36346.1|bibcode=2015Geo....43..195C }}</ref><ref>{{cite journal |last1=Johnson |first1=C.N. |last2=Alroy |first2=J. |last3=Beeton |first3=N.J. |last4=Bird |first4=M.I. |last5=Brook |first5=B.W. |last6=Cooper |first6=A. |last7=Gillespie |first7=R. |last8=Herrando-Pérez |first8=S. |last9=Jacobs |first9=Z. |last10=Miller |first10=G.H. |last11=Prideaux |first11=G.J. |display-authors=6 |year=2016 |title=What caused extinction of the Pleistocene megafauna of Sahul? |journal=Proceedings of the Royal Society B: Biological Sciences |volume=283 |issue=1824 |pages=20152399 |doi=10.1098/rspb.2015.2399 |issn=0962-8452 |pmc=4760161 |pmid=26865301 }}</ref><ref>{{cite journal|first1=S. A.|last1=Hocknull|first2=R.|last2=Lewis|first3=L. J.|last3=Arnold|first4=T.|last4=Pietsch|first5=R.|last5=Joannes-Boyau|first6=G. J.|last6=Price|first7=P.|last7=Moss|first8=R.|last8=Wood|first9=A.|last9=Dosseto|first10=J.|last10=Louys|first11=J.|last11=Olley|first12=R. A.|last12=Lawrence|year=2020|title=Extinction of eastern Sahul megafauna coincides with sustained environmental deterioration|journal=Nature Communications|volume=11|issue=1 |page=2250|doi=10.1038/s41467-020-15785-w|pmc=7231803|pmid=32418985|bibcode=2020NatCo..11.2250H }}</ref><ref>{{cite journal|first1=C. W.|last1=Kemp|first2=J.|last2=Tibby|first3=L. J.|last3=Arnold|first4=C.|last4=Barr|year=2019|title=Australian hydroclimate during Marine Isotope Stage 3: a synthesis and review|journal=Quaternary Science Reviews|volume=204|pages=94–104|doi=10.1016/j.quascirev.2018.11.016|bibcode=2019QSRv..204...94K |s2cid=134214134 }}</ref> Their demise may have been the result of a combination of climatic change, human hunting, and human-driven landscape changes.<ref name=David2021/>